Assertion: In some cases, sodium may be a ninth essential micronutrient.
Reason: Essential micronutrients are needed by the plants only in tiny quantities.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Majority of the nutrients that are essential for the growth and development of plants become available to the roots due to:
1. Microbial actions in the soil
2. Wet deposition from the atmosphere
3. Addition of fertilizers
4. Weathering and breakdown of rocks